<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Document</title>
    <script src="../vue.js"></script>
</head>

<body>
    <div id="app">
        <input type="text" @input="add" v-model="myadd" />
        <ul>
            <li v-for="item in list">{{item}}</li>
        </ul>
    </div>

    <script>
        new Vue({
            el: "#app",
            data: {
                myadd: "",
                list: ["a", "b"],
                lists: ["a", "b"],
            },
            methods: {
                add() {
                    console.log(this.myadd);
                    // this.list.push(this.myadd);
                    this.list = this.lists.filter((item) => item.includes(this.myadd));
                },
            },
        });
    </script>
</body>

</html>